1. Field of the Invention
The invention relates to a fuel supply system for supplying an internal combustion engine, particularly a motor vehicle, with fuel as well as a method for controlling the fuel supply of an internal combustion engine.
2. Description of Related Art
For supplying an internal combustion engine with fuel, it is known to dispose an electric fuel pump in a fuel tank, feeding fuel to the internal combustion engine via a fuel line. From German Patent DE 199 48 170 A1, it is known to carry off a part of the fed fuel via a shunt to operate a sucking jet pump therewith. By the operation of the sucking jet pump, it is possible to sufficiently supply a fuel pump arranged in a surge pot with fuel so that the fuel pump feeds enough fuel to supply the internal combustion engine. Further, it is known to return a part of the fuel fed by the fuel pump to the fuel pump, particularly into the surge pot, via a return line. Due to the fact that a part of the fed fuel is circulated, the cooling of the fuel pump is considerably improved.
In such fuel supply systems, the electric fuel pump and/or the number of the used sucking jet pumps is intentionally over dimensioned to provide for a sufficient supply of fuel when the internal combustion engine is started and there only is a low board voltage for the operation of the electric fuel pump. Because of the over dimensioning, such fuel supply systems are expensive and require a correspondingly large building space. Further, it requires a great lot of time until the desired operational state of the internal combustion engine is reached after the start since a great part of the fed fuel quantity is not used for the internal combustion engine but for the sucking jet pumps provided.
It is further known from DE 199 48 170 A1 to control the flow rate of the electric fuel pump in dependence on the pressure in the fuel line. Since the course of the board voltage is not completely known when the internal combustion engine is started, a reliable fuel supply of the internal combustion engine by controlling the fuel pump is not possible. To guarantee a reliable fuel supply during the start of the internal combustion engine as well, an intentional over dimensioning of the employed fuel supply system is thus required.